<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin:0;
            padding: 0;
        }
        /*让容器的高度和宽度都充满全屏*/
        html,body{
            width: 100%;
            height: 100%;
        }
        body{
            background-color: pink;
            display:flex;
            flex-direction: row;
            align-items: center;
            justify-content: center;
        }
        .heart{
            width: 200px;
            height: 200px;
            background-color: red;
            position: relative;
            transform:rotate(45deg);
            animation:heartbit 1s alternate infinite;
            box-shadow: 0 0 30px red;
        }
        .heart::before{
            content:"";
            width:200px;
            height:100px;
            background-color:red;
            position:absolute;
            left:0;
            top:-99px;
            border-radius:100px 100px 0 0;
            box-shadow: 0 0 30px red;
        }
        .heart::after{
            content:"";
            width:100px;
            height:200px;
            background-color: red;
            position:absolute;
            left:-99px;
            top:0;
            border-radius:100px 0 0 100px;
            box-shadow: 0 0 30px red;
        }

        /*实现动画，让心跳动起来*/
        @keyframes heartbit{
            0%{
                transform:rotate(45deg) scale(0.6);
            }
            
            100%{
                transform:rotate(45deg) scale(1.4);
            }
        }
    </style>

</head>
<body>
    
    <div class="heart"></div>
    
</body>
</html>